Move and organize tests into subfolders

9 files changed, 2443 insertions, 0 deletions

diff --git a/tests/core/templates/test_command_queue.h b/tests/core/templates/test_command_queue.h
new file mode 100644
index 0000000000..5d228f2bf6
--- /dev/null
+++ b/tests/core/templates/test_command_queue.h
@@ -0,0 +1,431 @@
+/*************************************************************************/
+/*  test_command_queue.h                                                 */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef TEST_COMMAND_QUEUE_H
+#define TEST_COMMAND_QUEUE_H
+
+#include "core/config/project_settings.h"
+#include "core/math/random_number_generator.h"
+#include "core/os/os.h"
+#include "core/os/thread.h"
+#include "core/templates/command_queue_mt.h"
+#include "tests/test_macros.h"
+
+#if !defined(NO_THREADS)
+
+namespace TestCommandQueue {
+
+class ThreadWork {
+	Semaphore thread_sem;
+	Semaphore main_sem;
+	Mutex mut;
+	int threading_errors = 0;
+	enum State {
+		MAIN_START,
+		MAIN_DONE,
+		THREAD_START,
+		THREAD_DONE,
+	} state;
+
+public:
+	ThreadWork() {
+		mut.lock();
+		state = MAIN_START;
+	}
+	~ThreadWork() {
+		CHECK_MESSAGE(threading_errors == 0, "threads did not lock/unlock correctly");
+	}
+	void thread_wait_for_work() {
+		thread_sem.wait();
+		mut.lock();
+		if (state != MAIN_DONE) {
+			threading_errors++;
+		}
+		state = THREAD_START;
+	}
+	void thread_done_work() {
+		if (state != THREAD_START) {
+			threading_errors++;
+		}
+		state = THREAD_DONE;
+		mut.unlock();
+		main_sem.post();
+	}
+
+	void main_wait_for_done() {
+		main_sem.wait();
+		mut.lock();
+		if (state != THREAD_DONE) {
+			threading_errors++;
+		}
+		state = MAIN_START;
+	}
+	void main_start_work() {
+		if (state != MAIN_START) {
+			threading_errors++;
+		}
+		state = MAIN_DONE;
+		mut.unlock();
+		thread_sem.post();
+	}
+};
+
+class SharedThreadState {
+public:
+	ThreadWork reader_threadwork;
+	ThreadWork writer_threadwork;
+
+	CommandQueueMT command_queue = CommandQueueMT(true);
+
+	enum TestMsgType {
+		TEST_MSG_FUNC1_TRANSFORM,
+		TEST_MSG_FUNC2_TRANSFORM_FLOAT,
+		TEST_MSG_FUNC3_TRANSFORMx6,
+		TEST_MSGSYNC_FUNC1_TRANSFORM,
+		TEST_MSGSYNC_FUNC2_TRANSFORM_FLOAT,
+		TEST_MSGRET_FUNC1_TRANSFORM,
+		TEST_MSGRET_FUNC2_TRANSFORM_FLOAT,
+		TEST_MSG_MAX
+	};
+
+	Vector<TestMsgType> message_types_to_write;
+	bool during_writing = false;
+	int message_count_to_read = 0;
+	bool exit_threads = false;
+
+	Thread reader_thread;
+	Thread writer_thread;
+
+	int func1_count = 0;
+
+	void func1(Transform3D t) {
+		func1_count++;
+	}
+	void func2(Transform3D t, float f) {
+		func1_count++;
+	}
+	void func3(Transform3D t1, Transform3D t2, Transform3D t3, Transform3D t4, Transform3D t5, Transform3D t6) {
+		func1_count++;
+	}
+	Transform3D func1r(Transform3D t) {
+		func1_count++;
+		return t;
+	}
+	Transform3D func2r(Transform3D t, float f) {
+		func1_count++;
+		return t;
+	}
+
+	void add_msg_to_write(TestMsgType type) {
+		message_types_to_write.push_back(type);
+	}
+
+	void reader_thread_loop() {
+		reader_threadwork.thread_wait_for_work();
+		while (!exit_threads) {
+			if (message_count_to_read < 0) {
+				command_queue.flush_all();
+			}
+			for (int i = 0; i < message_count_to_read; i++) {
+				command_queue.wait_and_flush();
+			}
+			message_count_to_read = 0;
+
+			reader_threadwork.thread_done_work();
+			reader_threadwork.thread_wait_for_work();
+		}
+		command_queue.flush_all();
+		reader_threadwork.thread_done_work();
+	}
+	static void static_reader_thread_loop(void *stsvoid) {
+		SharedThreadState *sts = static_cast<SharedThreadState *>(stsvoid);
+		sts->reader_thread_loop();
+	}
+
+	void writer_thread_loop() {
+		during_writing = false;
+		writer_threadwork.thread_wait_for_work();
+		while (!exit_threads) {
+			Transform3D tr;
+			Transform3D otr;
+			float f = 1;
+			during_writing = true;
+			for (int i = 0; i < message_types_to_write.size(); i++) {
+				TestMsgType msg_type = message_types_to_write[i];
+				switch (msg_type) {
+					case TEST_MSG_FUNC1_TRANSFORM:
+						command_queue.push(this, &SharedThreadState::func1, tr);
+						break;
+					case TEST_MSG_FUNC2_TRANSFORM_FLOAT:
+						command_queue.push(this, &SharedThreadState::func2, tr, f);
+						break;
+					case TEST_MSG_FUNC3_TRANSFORMx6:
+						command_queue.push(this, &SharedThreadState::func3, tr, tr, tr, tr, tr, tr);
+						break;
+					case TEST_MSGSYNC_FUNC1_TRANSFORM:
+						command_queue.push_and_sync(this, &SharedThreadState::func1, tr);
+						break;
+					case TEST_MSGSYNC_FUNC2_TRANSFORM_FLOAT:
+						command_queue.push_and_sync(this, &SharedThreadState::func2, tr, f);
+						break;
+					case TEST_MSGRET_FUNC1_TRANSFORM:
+						command_queue.push_and_ret(this, &SharedThreadState::func1r, tr, &otr);
+						break;
+					case TEST_MSGRET_FUNC2_TRANSFORM_FLOAT:
+						command_queue.push_and_ret(this, &SharedThreadState::func2r, tr, f, &otr);
+						break;
+					default:
+						break;
+				}
+			}
+			message_types_to_write.clear();
+			during_writing = false;
+
+			writer_threadwork.thread_done_work();
+			writer_threadwork.thread_wait_for_work();
+		}
+		writer_threadwork.thread_done_work();
+	}
+	static void static_writer_thread_loop(void *stsvoid) {
+		SharedThreadState *sts = static_cast<SharedThreadState *>(stsvoid);
+		sts->writer_thread_loop();
+	}
+
+	void init_threads() {
+		reader_thread.start(&SharedThreadState::static_reader_thread_loop, this);
+		writer_thread.start(&SharedThreadState::static_writer_thread_loop, this);
+	}
+	void destroy_threads() {
+		exit_threads = true;
+		reader_threadwork.main_start_work();
+		writer_threadwork.main_start_work();
+
+		reader_thread.wait_to_finish();
+		writer_thread.wait_to_finish();
+	}
+};
+
+TEST_CASE("[CommandQueue] Test Queue Basics") {
+	const char *COMMAND_QUEUE_SETTING = "memory/limits/command_queue/multithreading_queue_size_kb";
+	ProjectSettings::get_singleton()->set_setting(COMMAND_QUEUE_SETTING, 1);
+	SharedThreadState sts;
+	sts.init_threads();
+
+	sts.add_msg_to_write(SharedThreadState::TEST_MSG_FUNC1_TRANSFORM);
+	sts.writer_threadwork.main_start_work();
+	sts.writer_threadwork.main_wait_for_done();
+	CHECK_MESSAGE(sts.func1_count == 0,
+			"Control: no messages read before reader has run.");
+
+	sts.message_count_to_read = 1;
+	sts.reader_threadwork.main_start_work();
+	sts.reader_threadwork.main_wait_for_done();
+	CHECK_MESSAGE(sts.func1_count == 1,
+			"Reader should have read one message");
+
+	sts.message_count_to_read = -1;
+	sts.reader_threadwork.main_start_work();
+	sts.reader_threadwork.main_wait_for_done();
+	CHECK_MESSAGE(sts.func1_count == 1,
+			"Reader should have read no additional messages from flush_all");
+
+	sts.add_msg_to_write(SharedThreadState::TEST_MSG_FUNC1_TRANSFORM);
+	sts.writer_threadwork.main_start_work();
+	sts.writer_threadwork.main_wait_for_done();
+
+	sts.message_count_to_read = -1;
+	sts.reader_threadwork.main_start_work();
+	sts.reader_threadwork.main_wait_for_done();
+	CHECK_MESSAGE(sts.func1_count == 2,
+			"Reader should have read one additional message from flush_all");
+
+	sts.destroy_threads();
+
+	CHECK_MESSAGE(sts.func1_count == 2,
+			"Reader should have read no additional messages after join");
+	ProjectSettings::get_singleton()->set_setting(COMMAND_QUEUE_SETTING,
+			ProjectSettings::get_singleton()->property_get_revert(COMMAND_QUEUE_SETTING));
+}
+
+TEST_CASE("[CommandQueue] Test Queue Wrapping to same spot.") {
+	const char *COMMAND_QUEUE_SETTING = "memory/limits/command_queue/multithreading_queue_size_kb";
+	ProjectSettings::get_singleton()->set_setting(COMMAND_QUEUE_SETTING, 1);
+	SharedThreadState sts;
+	sts.init_threads();
+
+	sts.add_msg_to_write(SharedThreadState::TEST_MSG_FUNC3_TRANSFORMx6);
+	sts.add_msg_to_write(SharedThreadState::TEST_MSG_FUNC3_TRANSFORMx6);
+	sts.add_msg_to_write(SharedThreadState::TEST_MSG_FUNC1_TRANSFORM);
+	sts.writer_threadwork.main_start_work();
+	sts.writer_threadwork.main_wait_for_done();
+
+	sts.message_count_to_read = -1;
+	sts.reader_threadwork.main_start_work();
+	sts.reader_threadwork.main_wait_for_done();
+	CHECK_MESSAGE(sts.func1_count == 3,
+			"Reader should have read at least three messages");
+
+	sts.add_msg_to_write(SharedThreadState::TEST_MSG_FUNC3_TRANSFORMx6);
+	sts.writer_threadwork.main_start_work();
+	sts.writer_threadwork.main_wait_for_done();
+	sts.add_msg_to_write(SharedThreadState::TEST_MSG_FUNC1_TRANSFORM);
+	sts.add_msg_to_write(SharedThreadState::TEST_MSG_FUNC3_TRANSFORMx6);
+	sts.writer_threadwork.main_start_work();
+	OS::get_singleton()->delay_usec(1000);
+
+	sts.message_count_to_read = -1;
+	sts.reader_threadwork.main_start_work();
+	OS::get_singleton()->delay_usec(1000);
+
+	sts.writer_threadwork.main_wait_for_done();
+	sts.reader_threadwork.main_wait_for_done();
+	CHECK_MESSAGE(sts.func1_count >= 3,
+			"Reader should have read at least three messages");
+
+	sts.message_count_to_read = 6 - sts.func1_count;
+	sts.reader_threadwork.main_start_work();
+
+	// The following will fail immediately.
+	// The reason it hangs indefinitely in engine, is all subsequent calls to
+	// CommandQueue.wait_and_flush_one will also fail.
+	sts.reader_threadwork.main_wait_for_done();
+
+	// Because looping around uses an extra message, easiest to consume all.
+	sts.message_count_to_read = -1;
+	sts.reader_threadwork.main_start_work();
+	sts.reader_threadwork.main_wait_for_done();
+	CHECK_MESSAGE(sts.func1_count == 6,
+			"Reader should have read both message sets");
+
+	sts.destroy_threads();
+
+	CHECK_MESSAGE(sts.func1_count == 6,
+			"Reader should have read no additional messages after join");
+	ProjectSettings::get_singleton()->set_setting(COMMAND_QUEUE_SETTING,
+			ProjectSettings::get_singleton()->property_get_revert(COMMAND_QUEUE_SETTING));
+}
+
+TEST_CASE("[CommandQueue] Test Queue Lapping") {
+	const char *COMMAND_QUEUE_SETTING = "memory/limits/command_queue/multithreading_queue_size_kb";
+	ProjectSettings::get_singleton()->set_setting(COMMAND_QUEUE_SETTING, 1);
+	SharedThreadState sts;
+	sts.init_threads();
+
+	sts.add_msg_to_write(SharedThreadState::TEST_MSG_FUNC1_TRANSFORM);
+	sts.add_msg_to_write(SharedThreadState::TEST_MSG_FUNC3_TRANSFORMx6);
+	sts.add_msg_to_write(SharedThreadState::TEST_MSG_FUNC3_TRANSFORMx6);
+	sts.writer_threadwork.main_start_work();
+	sts.writer_threadwork.main_wait_for_done();
+
+	// We need to read an extra message so that it triggers the dealloc logic once.
+	// Otherwise, the queue will be considered full.
+	sts.message_count_to_read = 3;
+	sts.reader_threadwork.main_start_work();
+	sts.reader_threadwork.main_wait_for_done();
+	CHECK_MESSAGE(sts.func1_count == 3,
+			"Reader should have read first set of messages");
+
+	sts.add_msg_to_write(SharedThreadState::TEST_MSG_FUNC3_TRANSFORMx6);
+	sts.add_msg_to_write(SharedThreadState::TEST_MSG_FUNC3_TRANSFORMx6);
+	sts.writer_threadwork.main_start_work();
+	// Don't wait for these, because the queue isn't big enough.
+	sts.writer_threadwork.main_wait_for_done();
+
+	sts.add_msg_to_write(SharedThreadState::TEST_MSG_FUNC2_TRANSFORM_FLOAT);
+	sts.writer_threadwork.main_start_work();
+	OS::get_singleton()->delay_usec(1000);
+
+	sts.message_count_to_read = 3;
+	sts.reader_threadwork.main_start_work();
+	sts.reader_threadwork.main_wait_for_done();
+
+	sts.writer_threadwork.main_wait_for_done();
+
+	sts.message_count_to_read = -1;
+	sts.reader_threadwork.main_start_work();
+	sts.reader_threadwork.main_wait_for_done();
+
+	CHECK_MESSAGE(sts.func1_count == 6,
+			"Reader should have read rest of the messages after lapping writers.");
+
+	sts.destroy_threads();
+
+	CHECK_MESSAGE(sts.func1_count == 6,
+			"Reader should have read no additional messages after join");
+	ProjectSettings::get_singleton()->set_setting(COMMAND_QUEUE_SETTING,
+			ProjectSettings::get_singleton()->property_get_revert(COMMAND_QUEUE_SETTING));
+}
+
+TEST_CASE("[Stress][CommandQueue] Stress test command queue") {
+	const char *COMMAND_QUEUE_SETTING = "memory/limits/command_queue/multithreading_queue_size_kb";
+	ProjectSettings::get_singleton()->set_setting(COMMAND_QUEUE_SETTING, 1);
+	SharedThreadState sts;
+	sts.init_threads();
+
+	RandomNumberGenerator rng;
+
+	rng.set_seed(1837267);
+
+	int msgs_to_add = 2048;
+
+	for (int i = 0; i < msgs_to_add; i++) {
+		// randi_range is inclusive, so allow any enum value except MAX.
+		sts.add_msg_to_write((SharedThreadState::TestMsgType)rng.randi_range(0, SharedThreadState::TEST_MSG_MAX - 1));
+	}
+	sts.writer_threadwork.main_start_work();
+
+	int max_loop_iters = msgs_to_add * 2;
+	int loop_iters = 0;
+	while (sts.func1_count < msgs_to_add && loop_iters < max_loop_iters) {
+		int remaining = (msgs_to_add - sts.func1_count);
+		sts.message_count_to_read = rng.randi_range(1, remaining < 128 ? remaining : 128);
+		if (loop_iters % 3 == 0) {
+			sts.message_count_to_read = -1;
+		}
+		sts.reader_threadwork.main_start_work();
+		sts.reader_threadwork.main_wait_for_done();
+		loop_iters++;
+	}
+	CHECK_MESSAGE(loop_iters < max_loop_iters,
+			"Reader needed too many iterations to read messages!");
+	sts.writer_threadwork.main_wait_for_done();
+
+	sts.destroy_threads();
+
+	CHECK_MESSAGE(sts.func1_count == msgs_to_add,
+			"Reader should have read no additional messages after join");
+	ProjectSettings::get_singleton()->set_setting(COMMAND_QUEUE_SETTING,
+			ProjectSettings::get_singleton()->property_get_revert(COMMAND_QUEUE_SETTING));
+}
+} // namespace TestCommandQueue
+
+#endif // !defined(NO_THREADS)
+
+#endif // TEST_COMMAND_QUEUE_H
diff --git a/tests/core/templates/test_list.h b/tests/core/templates/test_list.h
new file mode 100644
index 0000000000..52d5edff70
--- /dev/null
+++ b/tests/core/templates/test_list.h
@@ -0,0 +1,548 @@
+/*************************************************************************/
+/*  test_list.h                                                          */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef TEST_LIST_H
+#define TEST_LIST_H
+
+#include "core/templates/list.h"
+
+#include "tests/test_macros.h"
+
+namespace TestList {
+
+static void populate_integers(List<int> &p_list, List<int>::Element *r_elements[], int num_elements) {
+	p_list.clear();
+	for (int i = 0; i < num_elements; ++i) {
+		List<int>::Element *n = p_list.push_back(i);
+		r_elements[i] = n;
+	}
+}
+
+TEST_CASE("[List] Push/pop back") {
+	List<String> list;
+
+	List<String>::Element *n;
+	n = list.push_back("A");
+	CHECK(n->get() == "A");
+	n = list.push_back("B");
+	CHECK(n->get() == "B");
+	n = list.push_back("C");
+	CHECK(n->get() == "C");
+
+	CHECK(list.size() == 3);
+	CHECK(!list.is_empty());
+
+	String v;
+	v = list.back()->get();
+	list.pop_back();
+	CHECK(v == "C");
+	v = list.back()->get();
+	list.pop_back();
+	CHECK(v == "B");
+	v = list.back()->get();
+	list.pop_back();
+	CHECK(v == "A");
+
+	CHECK(list.size() == 0);
+	CHECK(list.is_empty());
+
+	CHECK(list.back() == nullptr);
+	CHECK(list.front() == nullptr);
+}
+
+TEST_CASE("[List] Push/pop front") {
+	List<String> list;
+
+	List<String>::Element *n;
+	n = list.push_front("A");
+	CHECK(n->get() == "A");
+	n = list.push_front("B");
+	CHECK(n->get() == "B");
+	n = list.push_front("C");
+	CHECK(n->get() == "C");
+
+	CHECK(list.size() == 3);
+	CHECK(!list.is_empty());
+
+	String v;
+	v = list.front()->get();
+	list.pop_front();
+	CHECK(v == "C");
+	v = list.front()->get();
+	list.pop_front();
+	CHECK(v == "B");
+	v = list.front()->get();
+	list.pop_front();
+	CHECK(v == "A");
+
+	CHECK(list.size() == 0);
+	CHECK(list.is_empty());
+
+	CHECK(list.back() == nullptr);
+	CHECK(list.front() == nullptr);
+}
+
+TEST_CASE("[List] Set and get") {
+	List<String> list;
+	list.push_back("A");
+
+	List<String>::Element *n = list.front();
+	CHECK(n->get() == "A");
+
+	n->set("X");
+	CHECK(n->get() == "X");
+}
+
+TEST_CASE("[List] Insert before") {
+	List<String> list;
+	List<String>::Element *a = list.push_back("A");
+	List<String>::Element *b = list.push_back("B");
+	List<String>::Element *c = list.push_back("C");
+
+	list.insert_before(b, "I");
+
+	CHECK(a->next()->get() == "I");
+	CHECK(c->prev()->prev()->get() == "I");
+	CHECK(list.front()->next()->get() == "I");
+	CHECK(list.back()->prev()->prev()->get() == "I");
+}
+
+TEST_CASE("[List] Insert after") {
+	List<String> list;
+	List<String>::Element *a = list.push_back("A");
+	List<String>::Element *b = list.push_back("B");
+	List<String>::Element *c = list.push_back("C");
+
+	list.insert_after(b, "I");
+
+	CHECK(a->next()->next()->get() == "I");
+	CHECK(c->prev()->get() == "I");
+	CHECK(list.front()->next()->next()->get() == "I");
+	CHECK(list.back()->prev()->get() == "I");
+}
+
+TEST_CASE("[List] Insert before null") {
+	List<String> list;
+	List<String>::Element *a = list.push_back("A");
+	List<String>::Element *b = list.push_back("B");
+	List<String>::Element *c = list.push_back("C");
+
+	list.insert_before(nullptr, "I");
+
+	CHECK(a->next()->get() == "B");
+	CHECK(b->get() == "B");
+	CHECK(c->prev()->prev()->get() == "A");
+	CHECK(list.front()->next()->get() == "B");
+	CHECK(list.back()->prev()->prev()->get() == "B");
+	CHECK(list.back()->get() == "I");
+}
+
+TEST_CASE("[List] Insert after null") {
+	List<String> list;
+	List<String>::Element *a = list.push_back("A");
+	List<String>::Element *b = list.push_back("B");
+	List<String>::Element *c = list.push_back("C");
+
+	list.insert_after(nullptr, "I");
+
+	CHECK(a->next()->get() == "B");
+	CHECK(b->get() == "B");
+	CHECK(c->prev()->prev()->get() == "A");
+	CHECK(list.front()->next()->get() == "B");
+	CHECK(list.back()->prev()->prev()->get() == "B");
+	CHECK(list.back()->get() == "I");
+}
+
+TEST_CASE("[List] Find") {
+	List<int> list;
+	List<int>::Element *n[10];
+	// Indices match values.
+	populate_integers(list, n, 10);
+
+	for (int i = 0; i < 10; ++i) {
+		CHECK(n[i]->get() == list.find(i)->get());
+	}
+}
+
+TEST_CASE("[List] Erase (by value)") {
+	List<int> list;
+	List<int>::Element *n[4];
+	// Indices match values.
+	populate_integers(list, n, 4);
+
+	CHECK(list.front()->next()->next()->get() == 2);
+	bool erased = list.erase(2); // 0, 1, 3.
+	CHECK(erased);
+	CHECK(list.size() == 3);
+
+	// The pointer n[2] points to the freed memory which is not reset to zero,
+	// so the below assertion may pass, but this relies on undefined behavior.
+	// CHECK(n[2]->get() == 2);
+
+	CHECK(list.front()->get() == 0);
+	CHECK(list.front()->next()->next()->get() == 3);
+	CHECK(list.back()->get() == 3);
+	CHECK(list.back()->prev()->get() == 1);
+
+	CHECK(n[1]->next()->get() == 3);
+	CHECK(n[3]->prev()->get() == 1);
+
+	erased = list.erase(9000); // Doesn't exist.
+	CHECK(!erased);
+}
+
+TEST_CASE("[List] Erase (by element)") {
+	List<int> list;
+	List<int>::Element *n[4];
+	// Indices match values.
+	populate_integers(list, n, 4);
+
+	bool erased = list.erase(n[2]);
+	CHECK(erased);
+	CHECK(list.size() == 3);
+	CHECK(n[1]->next()->get() == 3);
+	CHECK(n[3]->prev()->get() == 1);
+}
+
+TEST_CASE("[List] Element erase") {
+	List<int> list;
+	List<int>::Element *n[4];
+	// Indices match values.
+	populate_integers(list, n, 4);
+
+	n[2]->erase();
+
+	CHECK(list.size() == 3);
+	CHECK(n[1]->next()->get() == 3);
+	CHECK(n[3]->prev()->get() == 1);
+}
+
+TEST_CASE("[List] Clear") {
+	List<int> list;
+	List<int>::Element *n[100];
+	populate_integers(list, n, 100);
+
+	list.clear();
+
+	CHECK(list.size() == 0);
+	CHECK(list.is_empty());
+}
+
+TEST_CASE("[List] Invert") {
+	List<int> list;
+	List<int>::Element *n[4];
+	populate_integers(list, n, 4);
+
+	list.reverse();
+
+	CHECK(list.front()->get() == 3);
+	CHECK(list.front()->next()->get() == 2);
+	CHECK(list.back()->prev()->get() == 1);
+	CHECK(list.back()->get() == 0);
+}
+
+TEST_CASE("[List] Move to front") {
+	List<int> list;
+	List<int>::Element *n[4];
+	populate_integers(list, n, 4);
+
+	list.move_to_front(n[3]);
+
+	CHECK(list.front()->get() == 3);
+	CHECK(list.back()->get() == 2);
+}
+
+TEST_CASE("[List] Move to back") {
+	List<int> list;
+	List<int>::Element *n[4];
+	populate_integers(list, n, 4);
+
+	list.move_to_back(n[0]);
+
+	CHECK(list.back()->get() == 0);
+	CHECK(list.front()->get() == 1);
+}
+
+TEST_CASE("[List] Move before") {
+	List<int> list;
+	List<int>::Element *n[4];
+	populate_integers(list, n, 4);
+
+	list.move_before(n[3], n[1]);
+
+	CHECK(list.front()->next()->get() == n[3]->get());
+}
+
+TEST_CASE("[List] Sort") {
+	List<String> list;
+	list.push_back("D");
+	list.push_back("B");
+	list.push_back("A");
+	list.push_back("C");
+
+	list.sort();
+
+	CHECK(list.front()->get() == "A");
+	CHECK(list.front()->next()->get() == "B");
+	CHECK(list.back()->prev()->get() == "C");
+	CHECK(list.back()->get() == "D");
+}
+
+TEST_CASE("[List] Swap adjacent front and back") {
+	List<int> list;
+	List<int>::Element *n[2];
+	populate_integers(list, n, 2);
+
+	list.swap(list.front(), list.back());
+
+	CHECK(list.front()->prev() == nullptr);
+	CHECK(list.front() != list.front()->next());
+
+	CHECK(list.front() == n[1]);
+	CHECK(list.back() == n[0]);
+
+	CHECK(list.back()->next() == nullptr);
+	CHECK(list.back() != list.back()->prev());
+}
+
+TEST_CASE("[List] Swap first adjacent pair") {
+	List<int> list;
+	List<int>::Element *n[4];
+	populate_integers(list, n, 4);
+
+	list.swap(n[0], n[1]);
+
+	CHECK(list.front()->prev() == nullptr);
+	CHECK(list.front() != list.front()->next());
+
+	CHECK(list.front() == n[1]);
+	CHECK(list.front()->next() == n[0]);
+	CHECK(list.back()->prev() == n[2]);
+	CHECK(list.back() == n[3]);
+
+	CHECK(list.back()->next() == nullptr);
+	CHECK(list.back() != list.back()->prev());
+}
+
+TEST_CASE("[List] Swap middle adjacent pair") {
+	List<int> list;
+	List<int>::Element *n[4];
+	populate_integers(list, n, 4);
+
+	list.swap(n[1], n[2]);
+
+	CHECK(list.front()->prev() == nullptr);
+
+	CHECK(list.front() == n[0]);
+	CHECK(list.front()->next() == n[2]);
+	CHECK(list.back()->prev() == n[1]);
+	CHECK(list.back() == n[3]);
+
+	CHECK(list.back()->next() == nullptr);
+}
+
+TEST_CASE("[List] Swap last adjacent pair") {
+	List<int> list;
+	List<int>::Element *n[4];
+	populate_integers(list, n, 4);
+
+	list.swap(n[2], n[3]);
+
+	CHECK(list.front()->prev() == nullptr);
+
+	CHECK(list.front() == n[0]);
+	CHECK(list.front()->next() == n[1]);
+	CHECK(list.back()->prev() == n[3]);
+	CHECK(list.back() == n[2]);
+
+	CHECK(list.back()->next() == nullptr);
+}
+
+TEST_CASE("[List] Swap first cross pair") {
+	List<int> list;
+	List<int>::Element *n[4];
+	populate_integers(list, n, 4);
+
+	list.swap(n[0], n[2]);
+
+	CHECK(list.front()->prev() == nullptr);
+
+	CHECK(list.front() == n[2]);
+	CHECK(list.front()->next() == n[1]);
+	CHECK(list.back()->prev() == n[0]);
+	CHECK(list.back() == n[3]);
+
+	CHECK(list.back()->next() == nullptr);
+}
+
+TEST_CASE("[List] Swap last cross pair") {
+	List<int> list;
+	List<int>::Element *n[4];
+	populate_integers(list, n, 4);
+
+	list.swap(n[1], n[3]);
+
+	CHECK(list.front()->prev() == nullptr);
+
+	CHECK(list.front() == n[0]);
+	CHECK(list.front()->next() == n[3]);
+	CHECK(list.back()->prev() == n[2]);
+	CHECK(list.back() == n[1]);
+
+	CHECK(list.back()->next() == nullptr);
+}
+
+TEST_CASE("[List] Swap edges") {
+	List<int> list;
+	List<int>::Element *n[4];
+	populate_integers(list, n, 4);
+
+	list.swap(n[1], n[3]);
+
+	CHECK(list.front()->prev() == nullptr);
+
+	CHECK(list.front() == n[0]);
+	CHECK(list.front()->next() == n[3]);
+	CHECK(list.back()->prev() == n[2]);
+	CHECK(list.back() == n[1]);
+
+	CHECK(list.back()->next() == nullptr);
+}
+
+TEST_CASE("[List] Swap middle (values check)") {
+	List<String> list;
+	List<String>::Element *n_str1 = list.push_back("Still");
+	List<String>::Element *n_str2 = list.push_back("waiting");
+	List<String>::Element *n_str3 = list.push_back("for");
+	List<String>::Element *n_str4 = list.push_back("Godot.");
+
+	CHECK(n_str1->get() == "Still");
+	CHECK(n_str4->get() == "Godot.");
+
+	CHECK(list.front()->get() == "Still");
+	CHECK(list.front()->next()->get() == "waiting");
+	CHECK(list.back()->prev()->get() == "for");
+	CHECK(list.back()->get() == "Godot.");
+
+	list.swap(n_str2, n_str3);
+
+	CHECK(list.front()->next()->get() == "for");
+	CHECK(list.back()->prev()->get() == "waiting");
+}
+
+TEST_CASE("[List] Swap front and back (values check)") {
+	List<Variant> list;
+	Variant str = "Godot";
+	List<Variant>::Element *n_str = list.push_back(str);
+	Variant color = Color(0, 0, 1);
+	List<Variant>::Element *n_color = list.push_back(color);
+
+	CHECK(list.front()->get() == "Godot");
+	CHECK(list.back()->get() == Color(0, 0, 1));
+
+	list.swap(n_str, n_color);
+
+	CHECK(list.front()->get() == Color(0, 0, 1));
+	CHECK(list.back()->get() == "Godot");
+}
+
+TEST_CASE("[List] Swap adjacent back and front (reverse order of elements)") {
+	List<int> list;
+	List<int>::Element *n[2];
+	populate_integers(list, n, 2);
+
+	list.swap(n[1], n[0]);
+
+	List<int>::Element *it = list.front();
+	while (it) {
+		List<int>::Element *prev_it = it;
+		it = it->next();
+		if (it == prev_it) {
+			FAIL_CHECK("Infinite loop detected.");
+			break;
+		}
+	}
+}
+
+static void swap_random(List<int> &p_list, List<int>::Element *r_elements[], size_t p_size, size_t p_iterations) {
+	Math::seed(0);
+
+	for (size_t test_i = 0; test_i < p_iterations; ++test_i) {
+		// A and B elements have corresponding indices as values.
+		const int a_idx = static_cast<int>(Math::rand() % p_size);
+		const int b_idx = static_cast<int>(Math::rand() % p_size);
+		List<int>::Element *a = p_list.find(a_idx); // via find.
+		List<int>::Element *b = r_elements[b_idx]; // via pointer.
+
+		int va = a->get();
+		int vb = b->get();
+
+		p_list.swap(a, b);
+
+		CHECK(va == a->get());
+		CHECK(vb == b->get());
+
+		size_t element_count = 0;
+
+		// Fully traversable after swap?
+		List<int>::Element *it = p_list.front();
+		while (it) {
+			element_count += 1;
+			List<int>::Element *prev_it = it;
+			it = it->next();
+			if (it == prev_it) {
+				FAIL_CHECK("Infinite loop detected.");
+				break;
+			}
+		}
+		// We should not lose anything in the process.
+		if (element_count != p_size) {
+			FAIL_CHECK("Element count mismatch.");
+			break;
+		}
+	}
+}
+
+TEST_CASE("[Stress][List] Swap random 100 elements, 500 iterations.") {
+	List<int> list;
+	List<int>::Element *n[100];
+	populate_integers(list, n, 100);
+	swap_random(list, n, 100, 500);
+}
+
+TEST_CASE("[Stress][List] Swap random 10 elements, 1000 iterations.") {
+	List<int> list;
+	List<int>::Element *n[10];
+	populate_integers(list, n, 10);
+	swap_random(list, n, 10, 1000);
+}
+} // namespace TestList
+
+#endif // TEST_LIST_H
diff --git a/tests/core/templates/test_local_vector.h b/tests/core/templates/test_local_vector.h
new file mode 100644
index 0000000000..eff2a16abc
--- /dev/null
+++ b/tests/core/templates/test_local_vector.h
@@ -0,0 +1,229 @@
+/*************************************************************************/
+/*  test_local_vector.h                                                  */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef TEST_LOCAL_VECTOR_H
+#define TEST_LOCAL_VECTOR_H
+
+#include "core/templates/local_vector.h"
+
+#include "tests/test_macros.h"
+
+namespace TestLocalVector {
+
+TEST_CASE("[LocalVector] Push Back.") {
+	LocalVector<int> vector;
+	vector.push_back(0);
+	vector.push_back(1);
+	vector.push_back(2);
+	vector.push_back(3);
+	vector.push_back(4);
+
+	CHECK(vector[0] == 0);
+	CHECK(vector[1] == 1);
+	CHECK(vector[2] == 2);
+	CHECK(vector[3] == 3);
+	CHECK(vector[4] == 4);
+}
+
+TEST_CASE("[LocalVector] Find.") {
+	LocalVector<int> vector;
+	vector.push_back(3);
+	vector.push_back(1);
+	vector.push_back(4);
+	vector.push_back(0);
+	vector.push_back(2);
+
+	CHECK(vector[0] == 3);
+	CHECK(vector[1] == 1);
+	CHECK(vector[2] == 4);
+	CHECK(vector[3] == 0);
+	CHECK(vector[4] == 2);
+
+	CHECK(vector.find(0) == 3);
+	CHECK(vector.find(1) == 1);
+	CHECK(vector.find(2) == 4);
+	CHECK(vector.find(3) == 0);
+	CHECK(vector.find(4) == 2);
+
+	CHECK(vector.find(-1) == -1);
+	CHECK(vector.find(5) == -1);
+}
+
+TEST_CASE("[LocalVector] Remove.") {
+	LocalVector<int> vector;
+	vector.push_back(0);
+	vector.push_back(1);
+	vector.push_back(2);
+	vector.push_back(3);
+	vector.push_back(4);
+
+	vector.remove(0);
+
+	CHECK(vector[0] == 1);
+	CHECK(vector[1] == 2);
+	CHECK(vector[2] == 3);
+	CHECK(vector[3] == 4);
+
+	vector.remove(2);
+
+	CHECK(vector[0] == 1);
+	CHECK(vector[1] == 2);
+	CHECK(vector[2] == 4);
+
+	vector.remove(1);
+
+	CHECK(vector[0] == 1);
+	CHECK(vector[1] == 4);
+
+	vector.remove(0);
+
+	CHECK(vector[0] == 4);
+}
+
+TEST_CASE("[LocalVector] Remove Unordered.") {
+	LocalVector<int> vector;
+	vector.push_back(0);
+	vector.push_back(1);
+	vector.push_back(2);
+	vector.push_back(3);
+	vector.push_back(4);
+
+	CHECK(vector.size() == 5);
+
+	vector.remove_unordered(0);
+
+	CHECK(vector.size() == 4);
+
+	CHECK(vector.find(0) == -1);
+	CHECK(vector.find(1) != -1);
+	CHECK(vector.find(2) != -1);
+	CHECK(vector.find(3) != -1);
+	CHECK(vector.find(4) != -1);
+
+	// Now the vector is no more ordered.
+	vector.remove_unordered(vector.find(3));
+
+	CHECK(vector.size() == 3);
+
+	CHECK(vector.find(3) == -1);
+	CHECK(vector.find(1) != -1);
+	CHECK(vector.find(2) != -1);
+	CHECK(vector.find(4) != -1);
+
+	vector.remove_unordered(vector.find(2));
+
+	CHECK(vector.size() == 2);
+
+	CHECK(vector.find(2) == -1);
+	CHECK(vector.find(1) != -1);
+	CHECK(vector.find(4) != -1);
+
+	vector.remove_unordered(vector.find(4));
+
+	CHECK(vector.size() == 1);
+
+	CHECK(vector.find(4) == -1);
+	CHECK(vector.find(1) != -1);
+
+	// Remove the last one.
+	vector.remove_unordered(0);
+
+	CHECK(vector.is_empty());
+	CHECK(vector.size() == 0);
+}
+
+TEST_CASE("[LocalVector] Erase.") {
+	LocalVector<int> vector;
+	vector.push_back(1);
+	vector.push_back(3);
+	vector.push_back(0);
+	vector.push_back(2);
+	vector.push_back(4);
+
+	CHECK(vector.find(2) == 3);
+
+	vector.erase(2);
+
+	CHECK(vector.find(2) == -1);
+	CHECK(vector.size() == 4);
+}
+
+TEST_CASE("[LocalVector] Size / Resize / Reserve.") {
+	LocalVector<int> vector;
+
+	CHECK(vector.is_empty());
+	CHECK(vector.size() == 0);
+	CHECK(vector.get_capacity() == 0);
+
+	vector.resize(10);
+
+	CHECK(vector.size() == 10);
+	CHECK(vector.get_capacity() >= 10);
+
+	vector.resize(5);
+
+	CHECK(vector.size() == 5);
+	// Capacity is supposed to change only when the size increase.
+	CHECK(vector.get_capacity() >= 10);
+
+	vector.remove(0);
+	vector.remove(0);
+	vector.remove(0);
+
+	CHECK(vector.size() == 2);
+	// Capacity is supposed to change only when the size increase.
+	CHECK(vector.get_capacity() >= 10);
+
+	vector.reset();
+
+	CHECK(vector.size() == 0);
+	CHECK(vector.get_capacity() == 0);
+
+	vector.reserve(3);
+
+	CHECK(vector.is_empty());
+	CHECK(vector.size() == 0);
+	CHECK(vector.get_capacity() >= 3);
+
+	vector.push_back(0);
+	vector.push_back(0);
+	vector.push_back(0);
+
+	CHECK(vector.size() == 3);
+	CHECK(vector.get_capacity() >= 3);
+
+	vector.push_back(0);
+
+	CHECK(vector.size() == 4);
+	CHECK(vector.get_capacity() >= 4);
+}
+} // namespace TestLocalVector
+
+#endif // TEST_LOCAL_VECTOR_H
diff --git a/tests/core/templates/test_lru.h b/tests/core/templates/test_lru.h
new file mode 100644
index 0000000000..9359909c53
--- /dev/null
+++ b/tests/core/templates/test_lru.h
@@ -0,0 +1,99 @@
+/*************************************************************************/
+/*  test_lru.h                                                           */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef TEST_LRU_H
+#define TEST_LRU_H
+
+#include "core/templates/lru.h"
+
+#include "tests/test_macros.h"
+
+namespace TestLRU {
+
+TEST_CASE("[LRU] Store and read") {
+	LRUCache<int, int> lru;
+
+	lru.set_capacity(3);
+	lru.insert(1, 1);
+	lru.insert(50, 2);
+	lru.insert(100, 5);
+
+	CHECK(lru.has(1));
+	CHECK(lru.has(50));
+	CHECK(lru.has(100));
+	CHECK(!lru.has(200));
+
+	CHECK(lru.get(1) == 1);
+	CHECK(lru.get(50) == 2);
+	CHECK(lru.get(100) == 5);
+
+	CHECK(lru.getptr(1) != nullptr);
+	CHECK(lru.getptr(1000) == nullptr);
+
+	lru.insert(600, 600); // Erase <50>
+	CHECK(lru.has(600));
+	CHECK(!lru.has(50));
+}
+
+TEST_CASE("[LRU] Resize and clear") {
+	LRUCache<int, int> lru;
+
+	lru.set_capacity(3);
+	lru.insert(1, 1);
+	lru.insert(2, 2);
+	lru.insert(3, 3);
+
+	CHECK(lru.get_capacity() == 3);
+
+	lru.set_capacity(5);
+	CHECK(lru.get_capacity() == 5);
+
+	CHECK(lru.has(1));
+	CHECK(lru.has(2));
+	CHECK(lru.has(3));
+	CHECK(!lru.has(4));
+
+	lru.set_capacity(2);
+	CHECK(lru.get_capacity() == 2);
+
+	CHECK(!lru.has(1));
+	CHECK(lru.has(2));
+	CHECK(lru.has(3));
+	CHECK(!lru.has(4));
+
+	lru.clear();
+	CHECK(!lru.has(1));
+	CHECK(!lru.has(2));
+	CHECK(!lru.has(3));
+	CHECK(!lru.has(4));
+}
+} // namespace TestLRU
+
+#endif // TEST_LRU_H
diff --git a/tests/core/templates/test_oa_hash_map.cpp b/tests/core/templates/test_oa_hash_map.cpp
new file mode 100644
index 0000000000..904c01642d
--- /dev/null
+++ b/tests/core/templates/test_oa_hash_map.cpp
@@ -0,0 +1,298 @@
+/*************************************************************************/
+/*  test_oa_hash_map.cpp                                                 */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#include "test_oa_hash_map.h"
+
+#include "core/os/os.h"
+#include "core/templates/oa_hash_map.h"
+
+namespace TestOAHashMap {
+
+struct CountedItem {
+	static int count;
+
+	int id = -1;
+	bool destroyed = false;
+
+	CountedItem() {
+		count++;
+	}
+
+	CountedItem(int p_id) :
+			id(p_id) {
+		count++;
+	}
+
+	CountedItem(const CountedItem &p_other) :
+			id(p_other.id) {
+		count++;
+	}
+
+	CountedItem &operator=(const CountedItem &p_other) = default;
+
+	~CountedItem() {
+		CRASH_COND(destroyed);
+		count--;
+		destroyed = true;
+	}
+};
+
+int CountedItem::count;
+
+MainLoop *test() {
+	OS::get_singleton()->print("\n\n\nHello from test\n");
+
+	// test element tracking.
+	{
+		OAHashMap<int, int> map;
+
+		map.set(42, 1337);
+		map.set(1337, 21);
+		map.set(42, 11880);
+
+		int value = 0;
+		map.lookup(42, value);
+
+		OS::get_singleton()->print("capacity  %d\n", map.get_capacity());
+		OS::get_singleton()->print("elements  %d\n", map.get_num_elements());
+
+		OS::get_singleton()->print("map[42] = %d\n", value);
+	}
+
+	// rehashing and deletion
+	{
+		OAHashMap<int, int> map;
+
+		for (int i = 0; i < 500; i++) {
+			map.set(i, i * 2);
+		}
+
+		for (int i = 0; i < 500; i += 2) {
+			map.remove(i);
+		}
+
+		uint32_t num_elems = 0;
+		for (int i = 0; i < 500; i++) {
+			int tmp;
+			if (map.lookup(i, tmp) && tmp == i * 2) {
+				num_elems++;
+			}
+		}
+
+		OS::get_singleton()->print("elements %d == %d.\n", map.get_num_elements(), num_elems);
+	}
+
+	// iteration
+	{
+		OAHashMap<String, int> map;
+
+		map.set("Hello", 1);
+		map.set("World", 2);
+		map.set("Godot rocks", 42);
+
+		for (OAHashMap<String, int>::Iterator it = map.iter(); it.valid; it = map.next_iter(it)) {
+			OS::get_singleton()->print("map[\"%s\"] = %d\n", it.key->utf8().get_data(), *it.value);
+		}
+	}
+
+	// stress test / test for issue #22928
+	{
+		OAHashMap<int, int> map;
+		int dummy = 0;
+		const int N = 1000;
+		uint32_t *keys = new uint32_t[N];
+
+		Math::seed(0);
+
+		// insert a couple of random keys (with a dummy value, which is ignored)
+		for (int i = 0; i < N; i++) {
+			keys[i] = Math::rand();
+			map.set(keys[i], dummy);
+
+			if (!map.lookup(keys[i], dummy)) {
+				OS::get_singleton()->print("could not find 0x%X despite it was just inserted!\n", unsigned(keys[i]));
+			}
+		}
+
+		// check whether the keys are still present
+		for (int i = 0; i < N; i++) {
+			if (!map.lookup(keys[i], dummy)) {
+				OS::get_singleton()->print("could not find 0x%X despite it has been inserted previously! (not checking the other keys, breaking...)\n", unsigned(keys[i]));
+				break;
+			}
+		}
+
+		delete[] keys;
+	}
+
+	// regression test / test for issue related to #31402
+	{
+		OS::get_singleton()->print("test for issue #31402 started...\n");
+
+		const int num_test_values = 12;
+		int test_values[num_test_values] = { 0, 24, 48, 72, 96, 120, 144, 168, 192, 216, 240, 264 };
+
+		int dummy = 0;
+		OAHashMap<int, int> map;
+		map.clear();
+
+		for (int i = 0; i < num_test_values; ++i) {
+			map.set(test_values[i], dummy);
+		}
+
+		OS::get_singleton()->print("test for issue #31402 passed.\n");
+	}
+
+	// test collision resolution, should not crash or run indefinitely
+	{
+		OAHashMap<int, int> map(4);
+		map.set(1, 1);
+		map.set(5, 1);
+		map.set(9, 1);
+		map.set(13, 1);
+		map.remove(5);
+		map.remove(9);
+		map.remove(13);
+		map.set(5, 1);
+	}
+
+	// test memory management of items, should not crash or leak items
+	{
+		// Exercise different patterns of removal
+		for (int i = 0; i < 4; ++i) {
+			{
+				OAHashMap<String, CountedItem> map;
+				int id = 0;
+				for (int j = 0; j < 100; ++j) {
+					map.insert(itos(j), CountedItem(id));
+				}
+				if (i <= 1) {
+					for (int j = 0; j < 100; ++j) {
+						map.remove(itos(j));
+					}
+				}
+				if (i % 2 == 0) {
+					map.clear();
+				}
+			}
+
+			if (CountedItem::count != 0) {
+				OS::get_singleton()->print("%d != 0 (not performing the other test sub-cases, breaking...)\n", CountedItem::count);
+				break;
+			}
+		}
+	}
+
+	// Test map with 0 capacity.
+	{
+		OAHashMap<int, String> original_map(0);
+		original_map.set(1, "1");
+		OS::get_singleton()->print("OAHashMap 0 capacity initialization passed.\n");
+	}
+
+	// Test copy constructor.
+	{
+		OAHashMap<int, String> original_map;
+		original_map.set(1, "1");
+		original_map.set(2, "2");
+		original_map.set(3, "3");
+		original_map.set(4, "4");
+		original_map.set(5, "5");
+
+		OAHashMap<int, String> map_copy(original_map);
+
+		bool pass = true;
+		for (
+				OAHashMap<int, String>::Iterator it = original_map.iter();
+				it.valid;
+				it = original_map.next_iter(it)) {
+			if (map_copy.lookup_ptr(*it.key) == nullptr) {
+				pass = false;
+			}
+			if (*it.value != *map_copy.lookup_ptr(*it.key)) {
+				pass = false;
+			}
+		}
+		if (pass) {
+			OS::get_singleton()->print("OAHashMap copy constructor test passed.\n");
+		} else {
+			OS::get_singleton()->print("OAHashMap copy constructor test FAILED.\n");
+		}
+
+		map_copy.set(1, "Random String");
+		if (*map_copy.lookup_ptr(1) == *original_map.lookup_ptr(1)) {
+			OS::get_singleton()->print("OAHashMap copy constructor, atomic copy test FAILED.\n");
+		} else {
+			OS::get_singleton()->print("OAHashMap copy constructor, atomic copy test passed.\n");
+		}
+	}
+
+	// Test assign operator.
+	{
+		OAHashMap<int, String> original_map;
+		original_map.set(1, "1");
+		original_map.set(2, "2");
+		original_map.set(3, "3");
+		original_map.set(4, "4");
+		original_map.set(5, "5");
+
+		OAHashMap<int, String> map_copy(100000);
+		map_copy.set(1, "Just a string.");
+		map_copy = original_map;
+
+		bool pass = true;
+		for (
+				OAHashMap<int, String>::Iterator it = map_copy.iter();
+				it.valid;
+				it = map_copy.next_iter(it)) {
+			if (original_map.lookup_ptr(*it.key) == nullptr) {
+				pass = false;
+			}
+			if (*it.value != *original_map.lookup_ptr(*it.key)) {
+				pass = false;
+			}
+		}
+		if (pass) {
+			OS::get_singleton()->print("OAHashMap assign operation test passed.\n");
+		} else {
+			OS::get_singleton()->print("OAHashMap assign operation test FAILED.\n");
+		}
+
+		map_copy.set(1, "Random String");
+		if (*map_copy.lookup_ptr(1) == *original_map.lookup_ptr(1)) {
+			OS::get_singleton()->print("OAHashMap assign operation atomic copy test FAILED.\n");
+		} else {
+			OS::get_singleton()->print("OAHashMap assign operation atomic copy test passed.\n");
+		}
+	}
+
+	return nullptr;
+}
+} // namespace TestOAHashMap
diff --git a/tests/core/templates/test_oa_hash_map.h b/tests/core/templates/test_oa_hash_map.h
new file mode 100644
index 0000000000..f229ac94ea
--- /dev/null
+++ b/tests/core/templates/test_oa_hash_map.h
@@ -0,0 +1,41 @@
+/*************************************************************************/
+/*  test_oa_hash_map.h                                                   */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef TEST_OA_HASH_MAP_H
+#define TEST_OA_HASH_MAP_H
+
+class MainLoop;
+
+namespace TestOAHashMap {
+
+MainLoop *test();
+}
+
+#endif // TEST_OA_HASH_MAP_H
diff --git a/tests/core/templates/test_ordered_hash_map.h b/tests/core/templates/test_ordered_hash_map.h
new file mode 100644
index 0000000000..35ce0fc656
--- /dev/null
+++ b/tests/core/templates/test_ordered_hash_map.h
@@ -0,0 +1,135 @@
+/*************************************************************************/
+/*  test_ordered_hash_map.h                                              */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef TEST_ORDERED_HASH_MAP_H
+#define TEST_ORDERED_HASH_MAP_H
+
+#include "core/templates/ordered_hash_map.h"
+
+#include "tests/test_macros.h"
+
+namespace TestOrderedHashMap {
+
+TEST_CASE("[OrderedHashMap] Insert element") {
+	OrderedHashMap<int, int> map;
+	OrderedHashMap<int, int>::Element e = map.insert(42, 84);
+
+	CHECK(e);
+	CHECK(e.key() == 42);
+	CHECK(e.get() == 84);
+	CHECK(e.value() == 84);
+	CHECK(map[42] == 84);
+	CHECK(map.has(42));
+	CHECK(map.find(42));
+}
+
+TEST_CASE("[OrderedHashMap] Overwrite element") {
+	OrderedHashMap<int, int> map;
+	map.insert(42, 84);
+	map.insert(42, 1234);
+
+	CHECK(map[42] == 1234);
+}
+
+TEST_CASE("[OrderedHashMap] Erase via element") {
+	OrderedHashMap<int, int> map;
+	OrderedHashMap<int, int>::Element e = map.insert(42, 84);
+
+	map.erase(e);
+	CHECK(!e);
+	CHECK(!map.has(42));
+	CHECK(!map.find(42));
+}
+
+TEST_CASE("[OrderedHashMap] Erase via key") {
+	OrderedHashMap<int, int> map;
+	map.insert(42, 84);
+	map.erase(42);
+	CHECK(!map.has(42));
+	CHECK(!map.find(42));
+}
+
+TEST_CASE("[OrderedHashMap] Size") {
+	OrderedHashMap<int, int> map;
+	map.insert(42, 84);
+	map.insert(123, 84);
+	map.insert(123, 84);
+	map.insert(0, 84);
+	map.insert(123485, 84);
+
+	CHECK(map.size() == 4);
+}
+
+TEST_CASE("[OrderedHashMap] Iteration") {
+	OrderedHashMap<int, int> map;
+	map.insert(42, 84);
+	map.insert(123, 12385);
+	map.insert(0, 12934);
+	map.insert(123485, 1238888);
+	map.insert(123, 111111);
+
+	Vector<Pair<int, int>> expected;
+	expected.push_back(Pair<int, int>(42, 84));
+	expected.push_back(Pair<int, int>(123, 111111));
+	expected.push_back(Pair<int, int>(0, 12934));
+	expected.push_back(Pair<int, int>(123485, 1238888));
+
+	int idx = 0;
+	for (OrderedHashMap<int, int>::Element E = map.front(); E; E = E.next()) {
+		CHECK(expected[idx] == Pair<int, int>(E.key(), E.value()));
+		++idx;
+	}
+}
+
+TEST_CASE("[OrderedHashMap] Const iteration") {
+	OrderedHashMap<int, int> map;
+	map.insert(42, 84);
+	map.insert(123, 12385);
+	map.insert(0, 12934);
+	map.insert(123485, 1238888);
+	map.insert(123, 111111);
+
+	const OrderedHashMap<int, int> const_map = map;
+
+	Vector<Pair<int, int>> expected;
+	expected.push_back(Pair<int, int>(42, 84));
+	expected.push_back(Pair<int, int>(123, 111111));
+	expected.push_back(Pair<int, int>(0, 12934));
+	expected.push_back(Pair<int, int>(123485, 1238888));
+
+	int idx = 0;
+	for (OrderedHashMap<int, int>::ConstElement E = const_map.front(); E; E = E.next()) {
+		CHECK(expected[idx] == Pair<int, int>(E.key(), E.value()));
+		++idx;
+	}
+}
+} // namespace TestOrderedHashMap
+
+#endif // TEST_ORDERED_HASH_MAP_H
diff --git a/tests/core/templates/test_paged_array.h b/tests/core/templates/test_paged_array.h
new file mode 100644
index 0000000000..7efd3799f3
--- /dev/null
+++ b/tests/core/templates/test_paged_array.h
@@ -0,0 +1,153 @@
+/*************************************************************************/
+/*  test_paged_array.h                                                   */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef TEST_PAGED_ARRAY_H
+#define TEST_PAGED_ARRAY_H
+
+#include "core/templates/paged_array.h"
+
+#include "thirdparty/doctest/doctest.h"
+
+namespace TestPagedArray {
+
+// PagedArray
+
+TEST_CASE("[PagedArray] Simple fill and refill") {
+	PagedArrayPool<uint32_t> pool;
+	PagedArray<uint32_t> array;
+	array.set_page_pool(&pool);
+
+	for (uint32_t i = 0; i < 123456; i++) {
+		array.push_back(i);
+	}
+	CHECK_MESSAGE(
+			array.size() == 123456,
+			"PagedArray should have 123456 elements.");
+
+	bool all_match = true;
+	for (uint32_t i = 0; i < 123456; i++) {
+		if (array[i] != i) {
+			all_match = false;
+			break;
+		}
+	}
+
+	CHECK_MESSAGE(
+			all_match,
+			"PagedArray elements should match from 0 to 123455.");
+
+	array.clear();
+
+	CHECK_MESSAGE(
+			array.size() == 0,
+			"PagedArray elements should be 0 after clear.");
+
+	for (uint32_t i = 0; i < 999; i++) {
+		array.push_back(i);
+	}
+	CHECK_MESSAGE(
+			array.size() == 999,
+			"PagedArray should have 999 elements.");
+
+	all_match = true;
+	for (uint32_t i = 0; i < 999; i++) {
+		if (array[i] != i) {
+			all_match = false;
+		}
+	}
+
+	CHECK_MESSAGE(
+			all_match,
+			"PagedArray elements should match from 0 to 998.");
+
+	array.reset(); //reset so pagepool can be reset
+	pool.reset();
+}
+
+TEST_CASE("[PagedArray] Shared pool fill, including merging") {
+	PagedArrayPool<uint32_t> pool;
+	PagedArray<uint32_t> array1;
+	PagedArray<uint32_t> array2;
+	array1.set_page_pool(&pool);
+	array2.set_page_pool(&pool);
+
+	for (uint32_t i = 0; i < 123456; i++) {
+		array1.push_back(i);
+	}
+	CHECK_MESSAGE(
+			array1.size() == 123456,
+			"PagedArray #1 should have 123456 elements.");
+
+	bool all_match = true;
+	for (uint32_t i = 0; i < 123456; i++) {
+		if (array1[i] != i) {
+			all_match = false;
+		}
+	}
+
+	CHECK_MESSAGE(
+			all_match,
+			"PagedArray #1 elements should match from 0 to 123455.");
+
+	for (uint32_t i = 0; i < 999; i++) {
+		array2.push_back(i);
+	}
+	CHECK_MESSAGE(
+			array2.size() == 999,
+			"PagedArray #2 should have 999 elements.");
+
+	all_match = true;
+	for (uint32_t i = 0; i < 999; i++) {
+		if (array2[i] != i) {
+			all_match = false;
+		}
+	}
+
+	CHECK_MESSAGE(
+			all_match,
+			"PagedArray #2 elements should match from 0 to 998.");
+
+	array1.merge_unordered(array2);
+
+	CHECK_MESSAGE(
+			array1.size() == 123456 + 999,
+			"PagedArray #1 should now be 123456 + 999 elements.");
+
+	CHECK_MESSAGE(
+			array2.size() == 0,
+			"PagedArray #2 should now be 0 elements.");
+
+	array1.reset(); //reset so pagepool can be reset
+	array2.reset(); //reset so pagepool can be reset
+	pool.reset();
+}
+} // namespace TestPagedArray
+
+#endif // TEST_PAGED_ARRAY_H
diff --git a/tests/core/templates/test_vector.h b/tests/core/templates/test_vector.h
new file mode 100644
index 0000000000..bfdf389aa7
--- /dev/null
+++ b/tests/core/templates/test_vector.h
@@ -0,0 +1,509 @@
+/*************************************************************************/
+/*  test_vector.h                                                        */
+/*************************************************************************/
+/*                       This file is part of:                           */
+/*                           GODOT ENGINE                                */
+/*                      https://godotengine.org                          */
+/*************************************************************************/
+/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur.                 */
+/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md).   */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person obtaining */
+/* a copy of this software and associated documentation files (the       */
+/* "Software"), to deal in the Software without restriction, including   */
+/* without limitation the rights to use, copy, modify, merge, publish,   */
+/* distribute, sublicense, and/or sell copies of the Software, and to    */
+/* permit persons to whom the Software is furnished to do so, subject to */
+/* the following conditions:                                             */
+/*                                                                       */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+
+#ifndef TEST_VECTOR_H
+#define TEST_VECTOR_H
+
+#include "core/templates/vector.h"
+
+#include "tests/test_macros.h"
+
+namespace TestVector {
+
+TEST_CASE("[Vector] Push back and append") {
+	Vector<int> vector;
+	vector.push_back(0);
+	vector.push_back(1);
+	vector.push_back(2);
+	vector.push_back(3);
+	// Alias for `push_back`.
+	vector.append(4);
+
+	CHECK(vector[0] == 0);
+	CHECK(vector[1] == 1);
+	CHECK(vector[2] == 2);
+	CHECK(vector[3] == 3);
+	CHECK(vector[4] == 4);
+}
+
+TEST_CASE("[Vector] Append array") {
+	Vector<int> vector;
+	vector.push_back(1);
+	vector.push_back(2);
+
+	Vector<int> vector_other;
+	vector_other.push_back(128);
+	vector_other.push_back(129);
+	vector.append_array(vector_other);
+
+	CHECK(vector.size() == 4);
+	CHECK(vector[0] == 1);
+	CHECK(vector[1] == 2);
+	CHECK(vector[2] == 128);
+	CHECK(vector[3] == 129);
+}
+
+TEST_CASE("[Vector] Insert") {
+	Vector<int> vector;
+	vector.insert(0, 2);
+	vector.insert(0, 8);
+	vector.insert(2, 5);
+	vector.insert(1, 5);
+	vector.insert(0, -2);
+
+	CHECK(vector.size() == 5);
+	CHECK(vector[0] == -2);
+	CHECK(vector[1] == 8);
+	CHECK(vector[2] == 5);
+	CHECK(vector[3] == 2);
+	CHECK(vector[4] == 5);
+}
+
+TEST_CASE("[Vector] Ordered insert") {
+	Vector<int> vector;
+	vector.ordered_insert(2);
+	vector.ordered_insert(8);
+	vector.ordered_insert(5);
+	vector.ordered_insert(5);
+	vector.ordered_insert(-2);
+
+	CHECK(vector.size() == 5);
+	CHECK(vector[0] == -2);
+	CHECK(vector[1] == 2);
+	CHECK(vector[2] == 5);
+	CHECK(vector[3] == 5);
+	CHECK(vector[4] == 8);
+}
+
+TEST_CASE("[Vector] Insert + Ordered insert") {
+	Vector<int> vector;
+	vector.ordered_insert(2);
+	vector.ordered_insert(8);
+	vector.insert(0, 5);
+	vector.ordered_insert(5);
+	vector.insert(1, -2);
+
+	CHECK(vector.size() == 5);
+	CHECK(vector[0] == 5);
+	CHECK(vector[1] == -2);
+	CHECK(vector[2] == 2);
+	CHECK(vector[3] == 5);
+	CHECK(vector[4] == 8);
+}
+
+TEST_CASE("[Vector] Fill large array and modify it") {
+	Vector<int> vector;
+	vector.resize(1'000'000);
+	vector.fill(0x60d07);
+
+	vector.write[200] = 0;
+	CHECK(vector.size() == 1'000'000);
+	CHECK(vector[0] == 0x60d07);
+	CHECK(vector[200] == 0);
+	CHECK(vector[499'999] == 0x60d07);
+	CHECK(vector[999'999] == 0x60d07);
+	vector.remove(200);
+	CHECK(vector[200] == 0x60d07);
+
+	vector.clear();
+	CHECK(vector.size() == 0);
+}
+
+TEST_CASE("[Vector] Copy creation") {
+	Vector<int> vector;
+	vector.push_back(0);
+	vector.push_back(1);
+	vector.push_back(2);
+	vector.push_back(3);
+	vector.push_back(4);
+
+	Vector<int> vector_other = Vector<int>(vector);
+	vector_other.remove(0);
+	CHECK(vector_other[0] == 1);
+	CHECK(vector_other[1] == 2);
+	CHECK(vector_other[2] == 3);
+	CHECK(vector_other[3] == 4);
+
+	// Make sure the original vector isn't modified.
+	CHECK(vector[0] == 0);
+	CHECK(vector[1] == 1);
+	CHECK(vector[2] == 2);
+	CHECK(vector[3] == 3);
+	CHECK(vector[4] == 4);
+}
+
+TEST_CASE("[Vector] Duplicate") {
+	Vector<int> vector;
+	vector.push_back(0);
+	vector.push_back(1);
+	vector.push_back(2);
+	vector.push_back(3);
+	vector.push_back(4);
+
+	Vector<int> vector_other = vector.duplicate();
+	vector_other.remove(0);
+	CHECK(vector_other[0] == 1);
+	CHECK(vector_other[1] == 2);
+	CHECK(vector_other[2] == 3);
+	CHECK(vector_other[3] == 4);
+
+	// Make sure the original vector isn't modified.
+	CHECK(vector[0] == 0);
+	CHECK(vector[1] == 1);
+	CHECK(vector[2] == 2);
+	CHECK(vector[3] == 3);
+	CHECK(vector[4] == 4);
+}
+
+TEST_CASE("[Vector] Get, set") {
+	Vector<int> vector;
+	vector.push_back(0);
+	vector.push_back(1);
+	vector.push_back(2);
+	vector.push_back(3);
+	vector.push_back(4);
+
+	CHECK(vector.get(0) == 0);
+	CHECK(vector.get(1) == 1);
+	vector.set(2, 256);
+	CHECK(vector.get(2) == 256);
+	CHECK(vector.get(3) == 3);
+
+	ERR_PRINT_OFF;
+	// Invalid (but should not crash): setting out of bounds.
+	vector.set(6, 500);
+	ERR_PRINT_ON;
+
+	CHECK(vector.get(4) == 4);
+}
+
+TEST_CASE("[Vector] To byte array") {
+	Vector<int> vector;
+	vector.push_back(0);
+	vector.push_back(-1);
+	vector.push_back(2008);
+	vector.push_back(999999999);
+
+	Vector<uint8_t> byte_array = vector.to_byte_array();
+	CHECK(byte_array.size() == 16);
+	// vector[0]
+	CHECK(byte_array[0] == 0);
+	CHECK(byte_array[1] == 0);
+	CHECK(byte_array[2] == 0);
+	CHECK(byte_array[3] == 0);
+
+	// vector[1]
+	CHECK(byte_array[4] == 255);
+	CHECK(byte_array[5] == 255);
+	CHECK(byte_array[6] == 255);
+	CHECK(byte_array[7] == 255);
+
+	// vector[2]
+	CHECK(byte_array[8] == 216);
+	CHECK(byte_array[9] == 7);
+	CHECK(byte_array[10] == 0);
+	CHECK(byte_array[11] == 0);
+
+	// vector[3]
+	CHECK(byte_array[12] == 255);
+	CHECK(byte_array[13] == 201);
+	CHECK(byte_array[14] == 154);
+	CHECK(byte_array[15] == 59);
+}
+
+TEST_CASE("[Vector] Subarray") {
+	Vector<int> vector;
+	vector.push_back(0);
+	vector.push_back(1);
+	vector.push_back(2);
+	vector.push_back(3);
+	vector.push_back(4);
+
+	Vector<int> subarray1 = vector.subarray(1, 2);
+	CHECK(subarray1.size() == 2);
+	CHECK(subarray1[0] == 1);
+	CHECK(subarray1[1] == 2);
+
+	Vector<int> subarray2 = vector.subarray(1, -1);
+	CHECK(subarray2.size() == 4);
+	CHECK(subarray2[0] == 1);
+	CHECK(subarray2[1] == 2);
+	CHECK(subarray2[2] == 3);
+	CHECK(subarray2[3] == 4);
+
+	Vector<int> subarray3 = vector.subarray(-2, -1);
+	CHECK(subarray3.size() == 2);
+	CHECK(subarray3[0] == 3);
+	CHECK(subarray3[1] == 4);
+
+	Vector<int> subarray4 = vector.subarray(-3, 3);
+	CHECK(subarray4.size() == 2);
+	CHECK(subarray4[0] == 2);
+	CHECK(subarray4[1] == 3);
+}
+
+TEST_CASE("[Vector] Find, has") {
+	Vector<int> vector;
+	vector.push_back(3);
+	vector.push_back(1);
+	vector.push_back(4);
+	vector.push_back(0);
+	vector.push_back(2);
+
+	CHECK(vector[0] == 3);
+	CHECK(vector[1] == 1);
+	CHECK(vector[2] == 4);
+	CHECK(vector[3] == 0);
+	CHECK(vector[4] == 2);
+
+	CHECK(vector.find(0) == 3);
+	CHECK(vector.find(1) == 1);
+	CHECK(vector.find(2) == 4);
+	CHECK(vector.find(3) == 0);
+	CHECK(vector.find(4) == 2);
+
+	CHECK(vector.find(-1) == -1);
+	CHECK(vector.find(5) == -1);
+
+	CHECK(vector.has(0));
+	CHECK(vector.has(1));
+	CHECK(vector.has(2));
+	CHECK(vector.has(3));
+	CHECK(vector.has(4));
+
+	CHECK(!vector.has(-1));
+	CHECK(!vector.has(5));
+}
+
+TEST_CASE("[Vector] Remove") {
+	Vector<int> vector;
+	vector.push_back(0);
+	vector.push_back(1);
+	vector.push_back(2);
+	vector.push_back(3);
+	vector.push_back(4);
+
+	vector.remove(0);
+
+	CHECK(vector[0] == 1);
+	CHECK(vector[1] == 2);
+	CHECK(vector[2] == 3);
+	CHECK(vector[3] == 4);
+
+	vector.remove(2);
+
+	CHECK(vector[0] == 1);
+	CHECK(vector[1] == 2);
+	CHECK(vector[2] == 4);
+
+	vector.remove(1);
+
+	CHECK(vector[0] == 1);
+	CHECK(vector[1] == 4);
+
+	vector.remove(0);
+
+	CHECK(vector[0] == 4);
+}
+
+TEST_CASE("[Vector] Remove and find") {
+	Vector<int> vector;
+	vector.push_back(0);
+	vector.push_back(1);
+	vector.push_back(2);
+	vector.push_back(3);
+	vector.push_back(4);
+
+	CHECK(vector.size() == 5);
+
+	vector.remove(0);
+
+	CHECK(vector.size() == 4);
+
+	CHECK(vector.find(0) == -1);
+	CHECK(vector.find(1) != -1);
+	CHECK(vector.find(2) != -1);
+	CHECK(vector.find(3) != -1);
+	CHECK(vector.find(4) != -1);
+
+	vector.remove(vector.find(3));
+
+	CHECK(vector.size() == 3);
+
+	CHECK(vector.find(3) == -1);
+	CHECK(vector.find(1) != -1);
+	CHECK(vector.find(2) != -1);
+	CHECK(vector.find(4) != -1);
+
+	vector.remove(vector.find(2));
+
+	CHECK(vector.size() == 2);
+
+	CHECK(vector.find(2) == -1);
+	CHECK(vector.find(1) != -1);
+	CHECK(vector.find(4) != -1);
+
+	vector.remove(vector.find(4));
+
+	CHECK(vector.size() == 1);
+
+	CHECK(vector.find(4) == -1);
+	CHECK(vector.find(1) != -1);
+
+	vector.remove(0);
+
+	CHECK(vector.is_empty());
+	CHECK(vector.size() == 0);
+}
+
+TEST_CASE("[Vector] Erase") {
+	Vector<int> vector;
+	vector.push_back(1);
+	vector.push_back(3);
+	vector.push_back(0);
+	vector.push_back(2);
+	vector.push_back(4);
+
+	CHECK(vector.find(2) == 3);
+
+	vector.erase(2);
+
+	CHECK(vector.find(2) == -1);
+	CHECK(vector.size() == 4);
+}
+
+TEST_CASE("[Vector] Size, resize, reserve") {
+	Vector<int> vector;
+	CHECK(vector.is_empty());
+	CHECK(vector.size() == 0);
+
+	vector.resize(10);
+
+	CHECK(vector.size() == 10);
+
+	vector.resize(5);
+
+	CHECK(vector.size() == 5);
+
+	vector.remove(0);
+	vector.remove(0);
+	vector.remove(0);
+
+	CHECK(vector.size() == 2);
+
+	vector.clear();
+
+	CHECK(vector.size() == 0);
+	CHECK(vector.is_empty());
+
+	vector.push_back(0);
+	vector.push_back(0);
+	vector.push_back(0);
+
+	CHECK(vector.size() == 3);
+
+	vector.push_back(0);
+
+	CHECK(vector.size() == 4);
+}
+
+TEST_CASE("[Vector] Sort") {
+	Vector<int> vector;
+	vector.push_back(2);
+	vector.push_back(8);
+	vector.push_back(-4);
+	vector.push_back(5);
+	vector.sort();
+
+	CHECK(vector.size() == 4);
+	CHECK(vector[0] == -4);
+	CHECK(vector[1] == 2);
+	CHECK(vector[2] == 5);
+	CHECK(vector[3] == 8);
+}
+
+TEST_CASE("[Vector] Sort custom") {
+	Vector<String> vector;
+	vector.push_back("world");
+	vector.push_back("World");
+	vector.push_back("Hello");
+	vector.push_back("10Hello");
+	vector.push_back("12Hello");
+	vector.push_back("01Hello");
+	vector.push_back("1Hello");
+	vector.push_back(".Hello");
+	vector.sort_custom<NaturalNoCaseComparator>();
+
+	CHECK(vector.size() == 8);
+	CHECK(vector[0] == ".Hello");
+	CHECK(vector[1] == "01Hello");
+	CHECK(vector[2] == "1Hello");
+	CHECK(vector[3] == "10Hello");
+	CHECK(vector[4] == "12Hello");
+	CHECK(vector[5] == "Hello");
+	CHECK(vector[6] == "world");
+	CHECK(vector[7] == "World");
+}
+
+TEST_CASE("[Vector] Search") {
+	Vector<int> vector;
+	vector.push_back(1);
+	vector.push_back(2);
+	vector.push_back(3);
+	vector.push_back(5);
+	vector.push_back(8);
+	CHECK(vector.bsearch(2, true) == 1);
+	CHECK(vector.bsearch(2, false) == 2);
+	CHECK(vector.bsearch(5, true) == 3);
+	CHECK(vector.bsearch(5, false) == 4);
+}
+
+TEST_CASE("[Vector] Operators") {
+	Vector<int> vector;
+	vector.push_back(2);
+	vector.push_back(8);
+	vector.push_back(-4);
+	vector.push_back(5);
+
+	Vector<int> vector_other;
+	vector_other.push_back(2);
+	vector_other.push_back(8);
+	vector_other.push_back(-4);
+	vector_other.push_back(5);
+
+	CHECK(vector == vector_other);
+
+	vector_other.push_back(10);
+	CHECK(vector != vector_other);
+}
+
+} // namespace TestVector
+
+#endif // TEST_VECTOR_H